American Indian/Alaskan native (AI/AN) children have overweight rates that are 18-30% higher than the general American population of children. Adult obesity has early antecedents, and date show that eating and physical activity behaviors are formed and set as early as 3 years of age, through primary socialization within families. Yet there are few, if any, obesity prevention programs that target children younger than 3 years of age. We propose a community-partnered randomized study to prevent early childhood overweight in American Indian (AI) children. A birth cohort of about 780 children from six Indian communities born over a period 18 months will be randomized by community to either a control (3 communities) or intervention condition (3 communities). The intervention comprises a community-wide intervention coupled with individualized family counseling to improve nutrition and physical activity in infants and toddlers. Nutrition goals are to increase breastfeeding initiation and sustainability, limit sugared beverages for infants and toddlers, and make healthful choices during weaning and solid food introduction. Physical activity goals include promoting motor development, limiting video/TV viewing and creating play opportunities for infants and toddlers. Intervention approaches and methods used in the pilot study on which this project is based will be combined with new formative data collected at the beginning of the project to enhance the intervention's feeding and physical activity components. Each component in the community-wide interventions will be collaboratively designed with the tribes, and tailored to each community's needs. Trained peer counselors will deliver the family interventions, during a series of 12 cluster visits, each covering a different developmental stage of the infant/toddler. The primary outcome is BMI Z scores at ages 24-30 months. (End of Abstract)